Card edge connector and method for connecting same

Abstract: A card edge connector includes inner housings that accommodate electrically conducting terminals. The inner housings are rotatably supported within a box-like outer housing. A rotatable range is regulated by projected portions of the respective housings being abutted against each other, so that an opening of the outer housing is kept open to allow an end portion of a printed board to be inserted. In addition, the terminals do not come in contact with each other, so that the circuit is kept from being shorted. When the insertion of the end portion into the outer housing is started, the upper inner housing rides over the end portion slightly. However, as the end portion is further inserted to the depth of the outer housing, introducing cams formed on a hood enclosing the end portion cause the upper inner housing to rotate with a slight insertion force, thereby causing the terminals to be urged into full engagement with the end portion of the printed board.

Description: BACKGROUND OF THE INVENTION The invention relates to a card edge connector for electrically connecting tongue portions of a plurality of terminals to a connecting section having a plurality of stripped terminals formed on an edge portion on both surfaces of a printed board. The invention also relates to a method for connecting opposed terminals to a printed board. A card edge connector is designed to connect an edge portion of a printed board between opposed terminals. A connecting section of the printed board has a plurality of terminals juxtaposed on both surfaces of the edge portion of the printed board. The terminals are formed by stripping parts of printed wire paths on the edge portion. A conventional card edge connector of this type is shown in Figures 6 and 7. In Figures 6 and 7, terminals (not shown) are formed on both surfaces of an end portion of a printed board. A slit-like insertion opening 4, which allows the end portion 1 of the card to be inserted therein, is formed in a box-like housing 3 of a card edge connector 2. The housing 3 holds terminals 5, 5 formed on opposite sides of a slender space 7 that communicates the insertion opening 4 within the depth of the housing 3. The respective terminal fittings 5, 5 have flexible tongue-like abutment portions 6 that project toward each other in the slender space 7. With this construction, to connect the card edge connector 2 to the end portion 1 of the printed board, the end portion 1 is aligned with the insertion opening 4 of the housing 3 and inserted or slid into the insertion opening 4 to an inserted position shown in Figure 7. During insertion, the end portion 1 pushingly expands the opposed vertically projecting tongue-like abutment portions 6 away from each other as the end portion moves toward the space 7 along a longitudinal axis of the insertion opening 4. In the aforementioned conventional card edge connector, the end portion 1 abuts against the abutment portions 6 obliquely to cause the abutment portions 6 to flex while sliding along the abutment portions 6 during insertion of the end portion 1. Accordingly, the end portion 1 is subjected to frictional and spring resistance at the time the end portion 1 pushingly expands the abutment portions 6. In some cases, the frictional resistance is of such a magnitude that the end portion 1 cannot slide well, thus deforming the abutment portions 6. In addition, the large frictional and spring resistance adversely affects the connecting operation. From document US-A-4 300 810 a zero insertion force connector for making contact with the electrical terminals of four printed wiring boards is known. Two pairs of parallel plates, each pair mounted for lateral movement and having a plurality of terminals for making contact with the corresponding electrical terminals of two printed wiring boards when inserted therebetween, are each separated and closed by the rotation of a shaft having two cam plates mounted near the opposite ends thereof. The two cam plates mounted next to the opposite ends of the two pairs of plates, respectively, converts the rotational movement of the shaft to the lateral movement of the two pairs of plates thereby separating and closing each pair of plates. I.e. in this arrangement an additional locking mechanism is provided which is operated after the printing boards have been inserted. Furthermore, the structure of this arrangement is very complex. Object of the invention is to provide a card edge connector capable of being easily connected to a plate member such as printed board with a small force and a corresponding method. The technical problem is solved by an apparatus in accordance with claim 1 and a method in accordance with claim 4. The rotation regulating mechanism may have projected portions formed on inner walls of the outer housing so as to confront the inner housing. Furthermore, the rotation regulating mechanism may have inner projected portions formed on outer walls of the inner housing so as to engage the outer housing. The inner housing may hold the abutment portions of electrically conducting terminals with the abutment portions projecting from a surface thereof, and the projected surfaces of the abutment portions are rotatably accommodated in the outer housing so as to face in a radial direction. The outer housing includes an insertion opening that allows insertion of the edge portion of the card edge. Because the rotation regulating mechanism is provided to regulate the rotatable range of the inner housing with respect to the outer housing, insertion of the edge portion of the card into the card edge insertion opening of the outer housing cannot be blocked by the inner housing. Further, while the rotating mechanism causes the inner housing to rotate after the edge portion of the plate member is being initially inserted into the outer housing, the projected surfaces of the abutment portions of the terminals in the inner housing are rotated so as to face the radial direction, which causes the abutment portions of the electrically conducting terminals in the inner housing to be abutted against the terminals formed on the surface of the edge portion of the plate member while the terminals approach the card edge. Moreover, rather than sliding along the exposed card edge terminals during insertion, the terminals of the inner housings engage the card edge near the completion of the insertion operation with the direction of approach of the inner housing terminals being substantially perpendicular to the surfaces of the exposed card terminals. Further, the projected portions may be formed so as to extend from the inner walls of the outer housing toward the inner housing, so that the projected portions regulate the rotatable range of the inner housing, which in turn contributes to maintaining the inner housing from blocking the insertion of the edge portion of the plate member into the insertion opening of the outer housing. Still further, the projected portions may be formed so as to be projected from the outer walls of the inner housing, so that the projected portions regulate the rotatable range of the inner housing while the inner housing abuts against the inner walls of the outer housing, the outer housing projected portions, and an additional inner housing. This also contributes to maintaining the inner housing from disturbing or blocking the insertion of the edge portion of the plate member into the insertion opening of the outer housing. As described in the foregoing, the invention has the effect of causing the inner housing, which is rotatably held within the outer housing, to hold the electrically conducting terminals, and allows the electrically conducting terminals to abut against the terminals on the edge portion of the card member as a result of the rotation or movement of the inner housing toward the printed board. Therefore, the edge portion of the card or plate member is no longer forced onto the abutment portions of the electrically conducting terminals, thereby preventing breakage and deformation of the electrically conducting terminals as well as implementing connection with a small force. In addition, when the inner housing is freely movable within the outer housing, the edge portion of the plate member entering from the insertion portion of the outer housing sometimes collides against the inner housing. While a spring may be provided to prevent this from happening, a technique employed by the invention to prevent blocking of the insertion of the edge portion of the plate member is to provide a regulator for restricting the rotation or movement range of the inner housing. This aspect of the invention is advantageous in that the inner housing is not required to be rotated against the force of the spring when the edge portion of the plate member is inserted, thereby allowing the abutment portions to be connected to the edge portion of the plate member using a small force. Moreover, the recessed and projected portions integrally formed with the outer housing and the inner housing regulate the rotatable range of the inner housing. Therefore, operation reliability is increased by maintaining the number of parts to a minimum. These and other aspects and advantages of the present invention are described in or apparent from the following detailed description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in detail with reference to the drawings, wherein: Figure 1 is an exploded perspective view of a card edge connector; Figure 2 is a sectional view showing a first stage of the process of connecting the card edge connector; Figure 3 is a sectional view showing the second stage of the process of connecting the card edge connector; Figure 4 is a sectional view showing the final condition of the process of connecting the card edge connector; Figure 5 is a sectional view showing the process of connecting the card edge connector in the case where no rotation regulating mechanism is provided; Figure 6 is a sectional view showing the process of connecting a conventional card edge connector; and Figure 7 is a sectional view showing the process of connecting the conventional card edge connector. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 is an exploded perspective view of a card edge connector. In Figure 1, a card edge connector 10 rotatably holds two flat box-like inner housings 30 inside a box-like outer housing 20. The outer housing 20 has an open rear surface and front side insertion opening 21. The insertion opening 21 is a horizontally extending slit-like opening. In a central portion on the upper wall of the outer housing 20, an axially extending lock arm 22 that is flexible in the vertical direction is provided. An upwardly projecting lock pawl 22a is formed in a central portion of the lock arm 22 and an operation knob 22b is also formed at the lock arm's rear end. A pair of notches 23 are formed on each of the upper and lower walls 20a, 20b at positions on each side of the lock arm 22 so as to be continuous to the front wall 20c of the lock arm 22. The pair of notches 23 communicate the inside of the outer housing 20 with the outside of the outer housing 20. Further, axially extending ribs 24 project vertically as well as outwardly from an end of each of the upper and lower walls 20a, 20b and from a middle portion of each lateral wall 20d. Bearing holes 25 are formed in two stages, upper and lower, in a portion closer to the rear end of each lateral wall 20d. An outer projected portion 26 is formed in relief at the middle position on the inner surface of each lateral wall 20d of the outer housing 20. Each outer projected portion 26 is formed such that the width of the rear end side is narrower than the width of the front end side. Each inner housing 30 has a width enabling it to be inserted into the outer housing 20. Cylindrical rotating shafts 31 can be journaled while being inserted into the bearing holes 25 and project from the rear sides of both lateral surfaces 30a, 30b of the inner housing 30. In addition, flat plate-like inner projected portions 32 project outwardly from the frontward ends of the lateral surfaces 30a, 30b on which the rotating shafts 31 are formed. The inner projected portions 32 abut directly against the inner lateral surfaces of lateral wall 20d of the outer housing 20. Because the outer projected portions 26 are formed in relief on the inner lateral surfaces of the outer housing 20 so as to leave spaces between projected portions 26 and upper and lower walls 20a, 20b, the inner projected portions 32 can move without abutting against the corresponding outer projected portions 26. Each inner housing 30 has horizontally juxtaposed terminal accommodating chambers 33 that can accommodate terminal fittings 41 with insertion openings 34 of the terminal fittings 41 opened on the rear side of the housing 30. In addition, each terminal fitting 41 has a vertically projected tongue-like abutment portion 41a. Communication openings 35 communicating with the terminal accommodating chambers 33 respectively are arranged on a surface of each inner housing 30 so that the abutment portions 41a can project from the inner housing 30 through the communication openings 35. An end portion 51 of a printed board projects from an electronic circuit chassis 50. In addition, a cylindrical hood 52 projects from the chassis and is formed to enclose the end portion 51. The inner circumferential surface of the hood 52 is formed to correspond to the outer profile of the outer housing 20. The inner surface of the hood includes grooves 53 that mate with respective ribs 24 of the outer housing 20, and a groove-like arm insertion portion 54 that mates and cooperates with the lock arm 22 of the outer housing 20. The arm insertion portion 54 projects upwardly. In addition, introducing cams or guide surfaces 55 are formed so as to project on the inner surface sides of the hood 52. The introducing cams 55 correspond to the notches 23 formed in both the upper and lower walls of the outer housing 20. Each introducing cam 55 is formed such that its height increases when moving toward the chassis 50. Although surfaces of the introducing cams 55 serving as sliding surfaces are shown as being flat, such surfaces may be made semi-circular in section in order to reduce friction at the time of sliding. Moreover, terminals 51a, which are formed by stripping the ends of printed wire paths, are provided on both surfaces of the end portion 51 of the printed board so as to correspond to the communication openings 35 of the inner housings 30. The operation of the thus constructed embodiment will now be described. The terminal fittings 41 are inserted into the terminal accommodating chambers 33 of the inner housings 30 through the insertion openings 34 before assembling the card edge connector 10. At the time of insertion, the abutment portions 41a are inserted into the inner peripheral wall of the accommodating chambers 33 on which the communication openings 35 are formed, so that when the terminal fittings 41 are pushed in, the abutment portions 41a project from the communication openings 35. However, the terminal fittings 41 may be inserted after the card edge connector 10 has been assembled. Then, the respective inner housings 30 are inserted into the opening on the rear side of the outer housing 20. The upper inner housing 30 is inserted with the communication openings 35 facing downward, so that the inner projected portions 32 stay above the outer projected portions 26 formed on the inner surfaces of the lateral walls 20d of the outer housing 20. Likewise, the lower inner housing 30 is inserted with the communication openings 35 facing upward, so that the inner projected portions 32 stay below the outer projected portions 26 formed on the inner surfaces of the lateral walls 20d of the outer housing 20. The outer housing 20 is thereafter flexed to pushingly expand the opening on the rear side in the horizontal direction to allow the rotating shafts 31 to pass through the bearing holes 25, thus completing the connection between the inner housing 30 and the outer housing 20. As shown in Figure 2, the lower inner housing 30 contacts the upper surface of the bottom wall 20b of the outer housing 20 and is, therefore, remotely located from the slit-like opening 21. However, in the upper inner housing 30, the inner projected portions 32 formed on the lateral surfaces 30a, 30b contact the upper portions of the outer projected portions 26 and are, therefore, located closer to the slit-like opening 21 within the rotatable range than the projected portion 32 on the lower inner housing. That is, the abutment of the inner projected portions 32 against the outer projected portions 26 allows the rotatable range of the upper inner housing 30 to be regulated, thus inhibiting the upper inner housing 30 from rotating toward the opening 21, although the upper inner housing 30 is located closest to the opening 21. This condition keeps the terminals 41a from contacting each other, thus preventing short-circuiting. Without such regulation, the upper inner housing 30 moves or rotates toward the lower inner housing 30, not only slightly closing the opening 21, but also causing short-circuiting between the terminals 41a of the upper and lower inner housings (see Figure 5). As a result, when inserting the end portion 51 of the printed board, the end portion 51 can undesirably abut against the front end of the upper inner housing 30, thus blocking insertion of the end portion. With the card edge connector 10 of the present invention, the card edge connector 10 is inserted into the hood 52, which projects from the electronic circuit chassis 50, as shown in Figure 2. As the card edge connector 10 is inserted from the front wall thereof with the respective ribs 24 of the outer housing 20 aligned with the grooves 53 of the hood 52, the introducing cams 55 are inserted into the notches 23 of the outer housing 20. However, because the height of the introducing cams 55 is small, the introducing cams 55 serve to position the outer housing 20 but do not allow themselves to be positively inserted into the outer housing 20. Both inner housings 30 are located at least at such positions as to prevent closing the opening 21, so that a gap is created or provided between the inner housings 30. Therefore, as the end portion 51 of the printed board initially enters the outer housing 20 through the insertion opening 21, the upper inner housing 30 rotates with the abutment portions 41a only slightly contacting the end portion 51, which causes the upper inner housing 30 to directly ride over the end portion 51. The lower inner housing 30 and the abutment portions 41a of the lower inner housing, however, only slightly contact with or nearly contact the end portion 51, which reduces the force required to push the end portion 51 during initial insertion. However, as the inner and outer housing assembly is further inserted toward the chassis to engage the highly projected portions of the introducing cams 55 with notches 23 as shown in Figure 3, the front end corner portions of the inner housings 30 abut against the slopes of the introducing cams 55. The introducing cams 55 formed on the upper and lower inner surfaces of the hood 52 increase in height or thickness when moving toward the chassis 50. Therefore, when the front end corner portions of the inner housings 30 are pushed into the hood 52 while abutted against the slopes of the introducing cams 55, both inner housings 30 are urged closer to each other toward the center. That is, the rotating mechanism allows the inner housings 30 to rotate when the front end corner portions of the inner housings 30 abut against the slopes of the introducing cams 55. As both inner housings 30 move closer toward each other, the abutment portions 41a of the terminal fittings 41, which project through the communication openings 35, are strongly urged into engagement with the terminals 51a formed on the surfaces of the end portion 51 of the printed board. Because the inner housings 30 receive the end portion 51 of the printed board, and then pivot about the rotating shafts 31, the terminal fittings 41 are urged onto the end portion 51 generally at an angle close to right angles. When the terminal fittings 41 engage the end portion 51 in this way, the abutment portions 41a are held down without undue deformation or the like. When the outer housing 20 has been completely inserted to the hood 52, both inner housings 30 confront each other generally in parallel with each other, thus being connected to the terminals 51a with the abutment portions 41a sandwiching the end portion 51 of the printed board as shown in Figure 4. As described in the foregoing, although the inner housings 30 that accommodate the electrically conducting terminals 41 therein are rotatably supported within the box-like outer housing 20, the rotatable range thereof is regulated by the projected portions 32, 26 of the respective housings 30, 20 being abutted against each other. Accordingly, the opening of the outer housing 20 is maintained or kept open to allow the end portion 51 of the printed board to be inserted thereinto. In addition, the terminals 41a do not come in contact with each other, so that the circuit is prevented from short-circuiting. When the insertion of the end portion 51 into the outer housing 20 is initially started, the upper inner housing 30 gently rides over the end portion 51. As the end portion 51 is further inserted, the introducing cams 55 formed on the hood 52 enclosing the end portion 51 cause the upper inner housing 30 to rotate with a slight insertion force, thereby causing the abutment portions 41a to be urged onto and connected to the terminals 51a.

Claims: A card edge connector (10) for holding the plurality of terminals (41), and for connecting the terminals to upper and lower surfaces of a card edge, the edge connector comprising: upper and lower inner housings (30) for holding the terminals in opposed relation corresponding to the upper and lower surfaces of the card edge; an outer housing (20) adapted to mount the inner housings, said outer housing having a card edge insertion opening (21) sized for insertion of the card edge, and an outer housing opening sized for insertion of the inner housing, said outer housing opening being located on a side formed on the outer housing that is opposite to a side on which the card edge insertion opening is formed; characterized in that said inner housings are rotatably supported in the outer housing and guide means (26, 32) are provided to regulate the rotatable range of the inner housings. The card edge connector according to claim 1, characterized in that said guide means (26, 32) include projected portions (26) formed on inner walls of the outer housing (20) that engage the inner housings (30). The card edge connector according to claim 1, characterized in that said guide means (26, 32) include projected portions (32) formed on outer walls of the inner housings (30) that engage the outer housing (20). A method of sandwiching a printed board between a plurality of opposed terminals using a card edge connector of claim 1, said method comprising: providing an outer housing (20) with an insertion opening (21) adapted to said printed board; disposing a pair of terminal housing members (30) within said outer housing, each of said terminal housing members being mounted on said outer housing on opposite sides of said insertion opening; inserting said printed board into said insertion opening while maintaining a space between said terminal housing members during initial insertion of the printed board; and moving the terminal housing members toward the insertion opening, thereby closing said space, when the printed board approaches a completely inserted position, thereby firmly sandwiching the printed board between the terminal housing members. The method of claim 4, further comprising providing guides (55) adjacent to said printed board, wherein said moving step includes rotating the terminal housing members (30) toward said insertion opening with said guides when the printed board approaches said completely inserted position. The method of claim 4, further comprising restricting movement of said terminal housing members (30) during said initial insertion.

Inventors: FUJITANI MITSUHIRO, MATSUSHITA YASUO, FUJITANI, MITSUHIRO, MATSUSHITA, YASUO, FUJITANI, MITSUHIRO, C/O SUMITOMO WIRING, MATSUSHITA, YASUO, C/O SUMITOMO WIRING
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1994
Main classification: H01R23
IPC codes: H01R12, H01R24